US 2013/0132054 A1 discloses an apparatus comprising an anatomical model generating unit for generating a patient-specific anatomical model of coronary arteries and the heart from medical image data of a patient and a functional model generating unit for generating a multi-scale functional model of coronary circulation based on the patient-specific anatomical model. The apparatus further comprises a simulation unit for simulating blood flow in at least one stenosis region of at least one coronary artery using the multi-scale functional model of coronary circulation. The simulation unit is particularly adapted to calculate hemodynamic quantities like fractional flow reserve (FFR) values for the at least one stenosis region.
The calculated hemodynamic quantities can be unreliable, which in turn can lead to an unreliable assessment of the at least one stenosis region based on the unreliable calculated hemodynamic quantities.